GILMORE SOILS REPORT 2-27-17 LMS
Recent efforts by land developers to promote the Gilmore area has generated interest in the area’s real estate as well as investigative interest from the Idaho Department of Environmental Quality, the Environmental Protection Agency (EPA) the Bureau of Land Management (BLM) Hazardous Materials department and the Idaho Department of Lands (IDL). The BLM is further involved due to its ownership of land in the Gilmore area. The reason for all the interest is the amount of metals left in the soils from Gilmore’s historic past
It has been verified that the area’s mining history has resulted in high metallic levels of lead, arsenic, antimony, cadmium, manganese and zinc. The advertised lots-for-sale drew the attention of state and federal agencies concerned about potential health risks. In May of 2016 the DEQ presented the Lemhi County Commissioners with an overview of concerns and its intention to study the area more closely.
Monday, February 27, 2017 results of the studies were reported to the board by Dana Swift who is with the DEQ Boise office of Waste Management and Remediation. She said the chief concern is the amount of lead and arsenic which is high enough to indicate action should be taken for the safety of anyone living there year around. At this point Gilmore is used more as a recreational area than it is for residential living.
According to Rob Hanson of the DEQ’s Mine Waste Management and Remediation Division in Boise, the levels are not high enough to generate Superfund interest or action.
Swift explained that soil assessments are part of the DEQ’s state-wide effort to identify possible health risks from abandoned mine sites. She said the EPA funded assessments are part of a totally volunteer program where property owners may request assessments and allow access to their properties. She said last Summer 18 Gilmore land owners, out of the 85 property owners contacted, requested soil testing. The townsite is divided into around 168 parcels.
Results of that testing confirm high levels of lead and arsenic in the areas of Gilmore most commonly used, specifically the roads. There are also results from 12 samples collected on surrounding BLM property. Swift said results for individual property owners who participated were sent directly to them.
The Regional Screening Level (RSL) of lead is the contaminant of most concern. Readings and maps of the area showing the concentrations along with a summation of the report were presented to the commissioners and to members of the public in attendance.
Swift said there is a definite correlation between concentrations of lead and concentrations of arsenic. The highest concentrations of lead are in the northern and western sections of the townsite and range from 16,900 to 32,300. She said some of the mine tailings piles are eroding onto BLM land where a ‘grab’ sample showed from 40,400 to 45,100.
Putting those figures into perspective Swift said, “If you were sampling your own yard or residential area for lead, the screening level that would trigger concern is 400 milligrams per kilogram and the highest concentration we are seeing out here is 40,000 milligrams per kilogram.” They also collected samples from a drainage pathway going towards the townsite and did some composite sampling. Additional details of those levels were in the report package.
The Gilmore Townsite is completely surrounded by BLM land and the agency is being pro-active by erecting informational signs which let visitors and land owners know of the possible health hazards. The DEQ is also providing land owners with health and safety information. Swift said information is being compiled from state and federal agencies about potential funding to keep the research program moving forward
Along with the report on contamination from lead she cited the arsenic levels recorded. Arsenic has been found to occur naturally throughout this area. Since it is known to be a human carcinogen acceptable levels are much lower. Swift said the level of concern for residential areas begins at point 68 milligrams per kilogram. Concentrations of 545 and 508 milligrams per kilogram were found where tailings material has gone onto BLM property and from 321 to 419 milligrams per kilogram in the northern portion of the Gilmore Townsite. The level-of-concern readings fluctuate throughout the townsite. The report said that other than lead and arsenic no additional metals above the RSL industrial levels were detected.
Gilmore’s glory days of mining on over 60 patented claims took place from the 1880’s to the 1930’s. The main commodities were lead, silver, copper, zinc and gold. Leadore’s railroad line was closed in the 1930’s as the mining interest waned and by 1965 Gilmore was virtually deserted.
As far as site mitigation Rob Hanson said this site does not rank in the major cleanup category because the exposure patterns which would trigger more action, such as year around residency, aren’t there. He said they’ll be looking at future study results in view of what the EPA can or might do to address the upstream source of contamination and he said the Idaho Department of Lands has some funding which could be used. He said there are also programs showing property owners how to protect contaminated areas by capping them with clean top soil.
Hanson said the DEQ’s main message is to provide information which will allow people to do what they want with their property in a safe way. He said that since the area is largely recreational the agency is looking at safety in terms of future use.
The County Commissioners expressed a desire to stay in the information loop and to make themselves available for future meetings.
The meeting was connected by telephone conference call to other Idaho Falls and Boise DEQ officials along with representatives from the EPA Idaho Operations Office, the BLM’s Hazardous Materials department and the Idaho Department of Lands
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